Add uprobes support

[lttng-modules.git] / wrapper / uprobes.h

diff --git a/wrapper/uprobes.h b/wrapper/uprobes.h
new file mode 100644 (file)
index 0000000..e38a541
--- /dev/null
+++ b/wrapper/uprobes.h
@@ -0,0 +1,87 @@
+#ifndef _LTTNG_WRAPPER_UPROBES_H
+#define _LTTNG_WRAPPER_UPROBES_H
+
+/*
+ * wrapper/uprobes.h
+ *
+ * wrapper around uprobes. Using KALLSYMS to get its address when
+ * available, else we need to have a kernel that exports this function to GPL
+ * modules.
+ *
+ * Copyright (C) 2013 Yannick Brosseau <yannick.brosseau@gmail.com>
+ * Copyright (C) 2017 Francis Deslauriers <francis.deslauriers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/version.h>
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,5,0))
+#include <linux/uprobes.h>
+
+/* Use kallsym lookup for version before 3.9. */
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,9,0))
+
+static inline
+int wrapper_uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
+{
+       return uprobe_register(inode, offset, uc);
+}
+
+static inline
+void wrapper_uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
+{
+       uprobe_unregister(inode, offset, uc);
+}
+
+#else /* Version < 3.9, use kallsym lookup. */
+#include "kallsyms.h"
+
+static inline
+int wrapper_uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
+{
+       int (*uprobe_register_sym)(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
+
+       uprobe_register_sym = (void *) kallsyms_lookup_funcptr("uprobe_register");
+
+       if (uprobe_register_sym) {
+               return uprobe_register_sym(inode, offset, uc);
+       } else {
+                printk(KERN_WARNING "LTTng: uprobe_register symbol lookup failed.\n");
+                return -EINVAL;
+       }
+}
+
+static inline
+void wrapper_uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
+{
+        int (*uprobe_unregister_sym)(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
+
+        uprobe_unregister_sym = (void *) kallsyms_lookup_funcptr("uprobe_unregister");
+
+        if (uprobe_unregister_sym) {
+                uprobe_unregister_sym(inode, offset, uc);
+        } else {
+                printk(KERN_WARNING "LTTng: uprobe_unregister symbol lookup failed.\n");
+                WARN_ON(1);
+        }
+}
+#endif
+#else
+/* Version <  3.5, before uprobe was added. */
+struct uprobe_consumer {};
+
+#endif
+#endif